Revelation
The story opens in 2157 with Admiral Jon Grissom, who is on his way to Arcturus aboard the SSV New Delhi to congratulate the graduates of the Alliance's N7 elite training program. Nine years ago, in 2148, scientists discovered a cache of alien technology buried on Mars. These aliens were known as the Protheans, who disappeared for unknown reasons 50,000 years ago. In 2149, an exploration team near the edge of the solar system discovered that Charon, Pluto's moon, was actually a mass relay, a dormant piece of ancient Prothean technology covered by sheets of ice. The Charon Relay granted instant travel across thousands of light-years to another mass relay in a different area of the galaxy. Jon Grissom led a team of brave men and women through the mass relay and became a hero of the Systems Alliance, a global coalition formed after the discovery of the Prothean cache on Mars. Grissom meets with David Edward Anderson, a promising young graduate of the N7 program, and reports that an unknown alien force has attacked an Alliance post at Shanxi. This begins the conflict later called the First Contact War between the Turian Hierarchy and the Alliance. Several battles ensued until the Citadel Council, a multi-species government devoted to preserving galactic peace and stability, intervened and stopped the conflict. Eight years later, humanity was recognized by the Council and granted an embassy. In 2165, then-Lieutenant Anderson answers an S.O.S. while patrolling the Skyllian Verge, an isolated region on the farthest fringes of Alliance space; the S.O.S. originating from a science facility on Sidon. Inside the facility, Anderson and his crew discover an elevator leading to an area underneath the main facility. They are attacked by several mercenaries and discover the dead bodies of the scientists who were stationed there. The evidence suggests they may have been betrayed by one of their own. One remaining mercenary manages to set off a bomb that destroys the entire lower level. Anderson and his crew barely escape with their lives. On the colony of Elysium, a scientist named Kahlee Sanders, recently stationed at Sidon, has gone AWOL with several classified files, intending on reporting her superiors for conducting illegal research. Hearing about the attack while at a bar, she leaves to figure out her next move and is attacked outside by a mercenary posing as an Alliance MP. Kahlee fights him off and, realising her escape from Sidon has put her in danger, runs to find help. Elsewhere, on Camala, a rich Batarian named Edan Had'dah meets with the Blue Suns, an infamous mercenary group in the Skyllian Verge. He hired them to attack the human research facility on Sidon. Once he learns of Sanders' leaving, he fears the information she had would point to his involvement and sends the mercs to deal with the loose end. He receives news of their failure and hires the Krogan bounty hunter Skarr to assassinate her. Anderson arrives at the Citadel, to meet with Ambassador Anita Goyle, the Alliance representative on the Citadel. Ambassador Goyle informs Anderson that the Sidon facility was researching AI. This is illegal under the Citadel Conventions after an incident 300 years ago, when the quarians created an artificial race—the geth—that eventually turned on them. She sends Anderson to locate Kahlee Sanders, who may know who was behind the attack and the whereabouts of Dr. Shu Qian, the brilliant scientist in charge of the Sidon facility. Meanwhile, the turian Spectre Saren Arterius has tracked an illegal weapons exchange to a warehouse on Juxhi. As a Spectre, Saren is above the law and, unfortunately, bears a grudge towards humanity after losing his brother in the First Contact War. After wiping out most of both parties, Saren interrogates a survivor, and learns that the weapons were meant for the Blue Suns, who were planning a major operation, but pulled out at the last minute to avoid Spectre attention. Saren's interest is piqued. After hunting a Blue Sun mercenary named Groto Ib-ba, Saren learns about Skarr and his new target. Tracking Kahlee to Elysium, Anderson is reunited with Jon Grissom, now retired, who turns out to be Kahlee's father. He tells him that he sent her away from Elysium to safety. Anderson leaves but a few hours later, Skarr shows up and attacks Grissom and Kahlee, who were in fact hiding in Grissom's house. Anderson returns and fights Skarr—in the middle of the battle Saren appears and drives Skarr off. However, the krogan manages to escape. Saren questions Kahlee about Sidon. She lies and says they were researching human biotics, knowing that if she revealed the truth about the research being done on Sidon, Saren would alert the Council and the Alliance would be in trouble. After Saren leaves, Kahlee tells Anderson that all the equipment for the project was supplied by the Dah'tan Manufacturing Company on Camala. They plan to sneak off Elysium and go to the Dah'tan facility. Meanwhile, Skarr returns to Edan who sends him and the Blue Sun mercenaries to destroy the Dah'tan facility and erase any information connecting him to the Sidon facility. Skarr destroys the facility, but Had'dah's contact, Jella, survives long enough for Saren to get Had'dah's name from her. Meanwhile, news of the AI research at the Sidon facility has reached the Council. When they rebuke Ambassador Goyle, she gets angry, pointing out the prominent role humans have in the galactic arena after such a short time, and negotiates a deal to get the Alliance off lightly with trade sanctions. Finally able to trust him, Kahlee makes a confession to Anderson. She knows who the traitor was at Sidon—Dr. Qian himself. Anderson is skeptical, but Kahlee explains Dr. Qian was studying something new, an alien artifact that might even pre-date the Protheans. After he started studying it in earnest, Dr. Qian's interest turned into a dangerous obsession (Indoctrination). She thinks Dr. Qian is working with Had'dah. Ambassador Goyle tells this to the Council as a show of good faith, and they decide to send Saren after Had'dah—Goyle asks for Anderson to be involved, as a possible Spectre candidate. Meanwhile, Kahlee is to be smuggled off Camala by Alliance marines. But Saren, knowing Had'dah is hunting Kahlee, sees this as a perfect opportunity to lure out the batarian, and leaks word to Had'dah's contacts. Skarr and the Blue Suns ambush the marines, destroy the SSV Iwo Jima, and capture Kahlee to help Dr. Qian's research. Anderson is furious at Saren, but he needs the Spectre's help to rescue Kahlee, who has been taken to an element zero refinery. Unknown to Anderson, Saren is now more interested in obtaining Dr. Qian's research for himself than saving Kahlee. Saren reluctantly agrees to give Anderson some time to find Kahlee before they blow the building. Anderson sneaks in and kills Skarr, rescuing Kahlee just as Saren destroys the refinery and kills Dr. Qian and Had'dah, stealing Dr. Qian's files. Returning to the Citadel, Anderson discovers Saren gave a damning report on his conduct during the mission. True or not, it means the Citadel Council is not willing to induct a human Spectre just yet. Without evidence, the Council is not prepared to go chasing after Dr. Qian's 'artifact' either. Despite the attraction between them, Anderson and Kahlee have to part ways. Anderson has his military career to follow, while Kahlee has been promoted and reassigned to a new classified posting. Meanwhile, Saren has been studying the research he stole, and is fascinated by the description of Sovereign, an enormous starship of devastating power. He believes his whole life, even his career as a Spectre, has just been a prelude to this discovery. Saren plans to use the data to find this warship, and use it to exact his revenge upon humanity.